Comments

Yes, those sentences are all grammatically correct. Which is better will depend upon your intention and the context in which you use them. The present perfect simple and continuous forms are often both possible and differ not in fact but in emphasis.

Hello Sir
Please tell me whether the following sentence is correct or not.
He is walking to and fro. I think he has been drinking.
Also these two: He is walking to and fro. I think he had been drinking.
He is walking to and fro.( I think) he must have been drinking.
Thank you.
Regards
Lal

Both of these can be correct, but it really depends on the context. We're happy to help you understand these forms if you can provide us with the context or you can also read more about these forms on our present perfect and past perfect pages.

Thanks for giving more context. What first comes to mind is 'This is the first time I've ever seen snow', but you could also say B. In the case of B, the past perfect is referring to the past time before a few moments ago (which also a past time) when you first saw snow.

I wouldn't say A because 'until now' includes the moment of speaking. In the moment of speaking you are clearly seeing snow and yet the verb is negative – so there is a kind of contradiction in the way the sentence is phrased.

Hello!
I wonder if we could say 'Someone has already played soccer (or any other games)' .
At the same time, can we say 'I'm playing soccer now.'?
In Japanese, concept of 'play' is 'do' rather than 'act'. So it is very confusing for us to use 'play'.
Your reply would be great help for me to understand English better.
Best regards,
Hiroko Takebuchi

When we say 'Someone has already played...' we are talking about some time in the past during the person's life. It tells us that the person has the experience of playing.

When we say 'I'm playing soccer now' we are talking about the current moment - the moment of speaking.

Play is most often used in English to describe participating in games (e.g. chess, cards, board games, computer games) and sports involving a ball (e.g. football, billiards, rugby). We use other verbs for different activities. For example, for activities which involve movement or travel we use go (e.g. go skiing, go running, go horse riding, go cycling), while for activities which focus on the use of the body we use do (e.g. do karate, do boxing, do yoga).